The delivery of radio frequency (RF) energy to target regions within tissue is known for a variety of purposes of particular interest to the present inventions. In one particular application, RF energy may be delivered to diseased regions (e.g., tumors) in tissue for the purpose of tissue necrosis. RF ablation of tumors is currently performed within one of two core technologies.
The first technology uses a single needle electrode, which when attached to a RF generator, emits RF energy from the exposed, uninsulated portion of the electrode. This energy translates into ion agitation, which is converted into heat and induces cellular death via coagulation necrosis. The second technology utilizes multiple needle electrodes, which have been designed for the treatment and necrosis of tumors in the liver and other solid tissues. PCT Publication WO 96/29946 and U.S. Pat. No. 6,379,353 disclose such probes.
Whichever technique is used for treatment, the target site, e.g., the tumor, is often dangerously close to vital organs or tissue (e.g., colon, prostate, gall bladder, or diaphragm). In many cases, to prevent or reduce the risk of thermally injuring the vital organs or tissue, the physician will opt to discontinue the procedure, or prematurely stop the procedure, resulting in a high likelihood of re-occurrence.
Thus, there is a need for an improved system and method for protecting vital organs or tissue from thermal damage that may otherwise result during ablation of adjacent tissue.